The present invention relates to a tubing for hydrostatic forming, a hydrostatic forming apparatus and a hydrostatic forming method using the apparatus.
In conventional hydrostatic forming, a tubing, for instance, an electric resistance welded tube, an aluminum alloy extrusion tube and the like, has been formed into a hydrostatic-formed article having a desired shape by using a hydrostatic forming apparatus. The hydrostatic forming apparatus has a specific nozzle for preventing the pressurized fluid from leaking from end surfaces of opposite end portions of the tubing upon applying pressurized fluid to the tubing through the nozzle. The nozzle is inserted into the opposite end portions of the tubing and seals the inside of the tubing. Japanese Patent Application First Publication No. 10-71433 discloses such a nozzle for hydrostatic forming as described above.
In addition, there has been proposed a hydrostatic forming apparatus having a pressing member that applies a pressing force onto end surfaces of the opposite end portions of the tubing in a longitudinal direction of the tubing, and a seal member that is inserted into the opposite end portions of the tubing and seal the inside of the tubing. Japanese Patent Application First Publication No. 2002-178050 discloses such a hydrostatic forming apparatus as described above.